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  • 1
    Electronic Resource
    Electronic Resource
    Potassium-Induced Release of Endogenous Amino Acids in the Guinea Pig Cochlea (1985)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 44 (1985), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Guinea pig cochleae were perfused with highpotassium solutions to depolarize hair cells artificially and induce the release of afferent neurotransmitter. Sequential injections of artificial perilymph containing 5 mM KCl, then 50 mM KCl, and finally 5 mM KCl were made into the scala tympani. This injection sequence was conducted under either normal divalent-cation conditions (2.0 mM CaCl2, 1.0 mM MgCl2) or calcium-deficient conditions intended to antagonize evoked transmitter release (0.1 mM CaCl2, 20.0 mM MgCl2). The levels of 21 endogenous primary amines in effluent collected from the scala vestibuli were determined by gradient-elution, reverse-phase HPLC using o-phthaldialdehyde-thiol adducts with fluorescence detection. Analyses indicated effluent concentrations of glutamate, taurine, and a coeluting taurine-γ-aminobutyrate (GABA) fraction (but not GABA alone) increased significantly after exposure to 50 mM KCl and returned to baseline levels after reintroduction of 5 mM KCl under normal divalent-cation conditions. Correspondent changes in the release of these constituents were significantly attenuated under calcium-deficient conditions. This was not the case for potassium-induced changes in the release of arginine, aspartate, and isoleucine. These data are consistent with the hypothesis that the receptoneuronal transmitter is glutamate and further suggest a calcium-dependent mechanism involving taurine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1985.tb07178.x
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  • 2
    Electronic Resource
    Electronic Resource
    Uronic Acid-Containing Glycosaminoglycans and Keratan Sulfate Are Present in the Tectorial Membrane of the Inner Ear: Functional Implications
    Amsterdam : Elsevier
    Archives of Biochemistry and Biophysics 307 (1993), S. 391-396 
    Details
    ISSN: 0003-9861
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1006/abbi.1993.1605
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  • 3
    Electronic Resource
    Electronic Resource
    Prolonged maintenance of endocochlear potential by vascular perfusion with media devoid of oxygen carriers (1984)
    Springer
    European archives of oto-rhino-laryngology and head & neck 239 (1984), S. 243-247 
    Details
    ISSN: 1434-4726
    Keywords: Endocochlear potential ; Vascular perfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A method is described for maintaining the cochlear potentials of the guinea pig via arterial perfusion of the surviving inner ear with an artificial medium devoid of oxygen carriers or oncotic agents. The endocochlear potential (EP) can be maintained at a normal level for periods in excess of 5 h; the responses of the EP to anoxia and to furosemide closely approximate those seen in the intact animal. This preparation may represent a simplified method for carrying out selected arterial perfusion experiments in the surviving inner ear.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00464250
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  • 4
    Electronic Resource
    Electronic Resource
    Die Regeneration der Mittelohrschleimhaut unter verschiedenen Bedingungen (1962)
    Springer
    European archives of oto-rhino-laryngology and head & neck 180 (1962), S. 549-553 
    Details
    ISSN: 1434-4726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Aus unseren Versuchen ergeben sich folgende Konsequenzen: 1. Die Implantation resorbierbarer Substanzen (Spongostan) in schleimhautentblößte Paukenhöhlen ist ungünstig, da die Gefahr besteht, daß diese Substanzen zu einer weitgehenden Obliteration der Paukenhöhle führen; keinesfalls regen sie die Epithelisierung der Defekte an. 2. Die Abdeckung der Schleimhautdefekte mittels Plastikfolien scheint im Sinne eines physiologischen Pflasters zu fungieren, unter dem sich eine zarte Granulationsgewebsschicht entwickelt, die relativ gute Tendenz zur Epithelisierung erkennen läßt. Voraussetzung ist allerdings eine möglichst exakte Adaptation der Folie an den Knochen. 3. Die postoperative Anwendung von Hydrocortison stört diesen Regenerationsprozeß nicht, sondern unterdrückt im Gegenteil die entzündliche Reaktion, was sich im Hinblick auf eine rasche Abheilung günstig auswirkt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02121510
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  • 5
    Electronic Resource
    Electronic Resource
    Influence of “loop” diuretics upon Na+K+-ATPase and adenylate cyclase of the stria vascularis (1977)
    Springer
    European archives of oto-rhino-laryngology and head & neck 217 (1977), S. 347-359 
    Details
    ISSN: 1434-4726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have previously found that the inhibition of strial Na+K+-ATPase by ethacrynic acid occurs at much higher concentrations (I50=5×10−3 M) than the inhibition of the endolymphatic potential (I50=1×10−5 M), which in itself is evidence against the concept that Na+K+-ATPase is a target of ethacrynic acid action in the stria vascularis. In order to check whether the stria vascularis accumulates the drug selectively (as is the case in tissue slices of kidney) we perfused the perilymphatic space with 14C-ethacrynic acid for 30 min. No accumulation of the drug above the concentration in the perfusion medium (5×10−5 to 5×10−3M) occurred in the stria vascularis. Since 30 min of perfusion produces maximal alterations of the endolymphatic potential at 1×10−4 M and above, and near maximal alterations at 5×10−5 M, Na+K+-ATPase can be excluded as a primary target of ethacrynic acid action upon the stria vascularis. No inhibition of Na+K+-ATPase by furosemide is detectable at 1×10−2 M. Adenylate cyclase of the stria vascularis is strongly inhibited by both ethacrynic acid and furosemide. In the case of ethacrynic acid the I50 (1×10−5 M) coincides with that of the endolymphatic potential. The I50 of adenylate cyclase with respect to furosemide is equally low (9×10−6 M), but the I50 of the endolymphatic potential is considerably higher (2×10−4 M). These results are consistent with the concept that interference with adenylate cyclase is a primary mode of action of ethacrynic acid and furosemide upon the stria vascularis. However, these data in themselves do not prove that this concept is valid under in vivo conditions. Both ethacrynic acid and furosemide are strong inhibitors of adenylate cyclase in the organ of Corti (I50= 8×10−6 and 3×10−6 M, respectively). Basal activities of adenylate cyclase in spiral ganglion, Reissner's membrane and macula sacculi are reported, as well as revised results for organ of Corti and stria vascularis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00465552
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  • 6
    Electronic Resource
    Electronic Resource
    Adenine nucleotides of the stria vascularis (1979)
    Springer
    European archives of oto-rhino-laryngology and head & neck 224 (1979), S. 89-95 
    Details
    ISSN: 1434-4726
    Keywords: Adenylate energy charge ; Energy status ; Phosphorylation state ; Inner ear perfusion ; Artificial blood ; Fluorocarbons ; Endolymphatic potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The levels of the adenine nucleotides ATP, ADP, and AMP in the stria vascularis were measured under normal conditions, and following various durations of ischemia. The concentrations of these compounds were used for the calculation of the adenylate energy charge, the energy status and the phosphorylation state of the stria. Following 10 min of ischemia the adenylate energy charge had decreased three fold, the energy status seven fold and the phosphorylation state 14 fold. To study the potential for recovery of strial function following various brief and prolonged ischemic intervals, a method for the perfusion of the ear via the anterior inferior cerebellar artery was developed. For various reasons it was found advantageous to use “artificial blood” as perfusate, relying upon fluorocarbons as oxygen carriers. The endolymphatic potential was used as electrical indicator of strial function. Recovery of the endolymphatic potential following brief periods of ischemia was paralleled by a corresponding increase of the ATP levels and a drastic decrease of the AMP levels of the stria vascularis. Preliminary results on the effects of substrate-free perfusion are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00455229
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  • 7
    Electronic Resource
    Electronic Resource
    Substitution of rubidium for potassium in perilymph (1979)
    Springer
    European archives of oto-rhino-laryngology and head & neck 224 (1979), S. 155-156 
    Details
    ISSN: 1434-4726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01108773
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  • 8
    Electronic Resource
    Electronic Resource
    Vascular perfusion of the cochlea: Effect of potassium-free and rubidium-substituted media (1979)
    Springer
    European archives of oto-rhino-laryngology and head & neck 225 (1979), S. 79-81 
    Details
    ISSN: 1434-4726
    Keywords: Endocochlear potential ; Vascular perfusion ; K+-free artificial blood ; Rb+-substituted blood
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary By means of vascular perfusion of the cochlea with K+-free synthetic blood, it is possible to maintain the endocochlear potential (EP) at normal or supernormal levels for periods of 20–42 min. The subsequent decline of the EP is comparatively slow. This is in contrast to the immediate onset and rapid decline of the EP during perilymphatic perfusion with K+-free media. Possible implications of these data concerning the mode of generation of the EP are briefly discussed. It is further shown, that synthetic blood, in which K+ is replaced by Rb+, maintains the EP at normal or near normal levels for 2 h.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00455206
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  • 9
    Electronic Resource
    Electronic Resource
    Die Beeinflussung der Mikrophonpotentiale durch endocochleare Applikation von Jodacetat (1963)
    Springer
    Cellular and molecular life sciences 19 (1963), S. 413-414 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The microphonic potentials of the cat were found to be reduced by endocochlear application of iodoacetate. The rate of decrease was markedly influenced by the intensity of the stimulus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02171519
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  • 10
    Electronic Resource
    Electronic Resource
    Eine Methode zur Untersuchung der Mikrophonpotentiale bei Ersatz der Perilymphe durch Lösungen verschiedener Zusammensetzung (1964)
    Springer
    Naturwissenschaften 51 (1964), S. 218-219 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00637170
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